updated 7:02 p.m. PT, Wed., July 8, 2009
SIOUX FALLS, South Dakota - Environmentalists who used National Park Service rock anchors to scale Mount Rushmore and unfurl an anti-global warming banner along President Abraham Lincoln's face Wednesday were charged with trespassing.

The 11 activists also were charged with the misdemeanor crime of climbing on Mount Rushmore National Monument, U.S. Attorney Marty Jackley said. They pleaded not guilty to all charges.

The environmental group Greenpeace said in a statement that its members used the park service's existing rock anchors to scale the mountain and unfurl a 65-foot (20-meter)-by-35-foot (10.7-meter) banner reading, "America honors leaders not politicians: Stop Global Warming."

Mount Rushmore Ranger Nav Singh said security warnings and tourists alerted officials when the banner was unrolled. The banner was removed about an hour after it was unfurled.

"You can't create any security system that's 100 percent fail-safe. There's just not enough resources for that," Singh said. "Determined individuals that are properly equipped and willing to do damage to government property can do this sort of thing."

Taken away in handcuffs and foot chains
Twelve people were taken away in handcuffs and foot chains. The 12th person taken into custody was released without being charged, Jackley said.

The National Park Service said in a statement that its staff and security detected the activists early and responded "within minutes." Visitors were not in danger, authorities said.

Park service staff remained at the mountain Wednesday to assess damage to the sculpture and security systems.

A number of demonstrations have taken place at Mount Rushmore over the years. In the early 1970s, American Indian Movement members tried several times to occupy and deface the monument. In August 1970, AIM members hung a banner with the words "Sioux Indian Power" on the monument.

In October 1987, Greenpeace activists tried unsuccessfully to unfurl a banner shaped like a gas mask over George Washington's face. That banner said, "We the People Say No to Acid Rain."

Security measures were beefed up after the September 11, 2001, terrorist attacks.

The 11 activists charged Wednesday were released on their own recognizance after the court hearing. A trespassing conviction carries up to six months in prison and a $5,000 fine, prosecutors said.